HIGHSULF(TM) processes increase the efficiency of amine desulfurization of gases: they increase emission of carbon dioxide above the absorber, significantly decrease the hydrocarbon content in the acid gas and increase the concentration of hydrogen sulfide, i.e., they increase the efficiency of extraction of sulfur in a Claus unit. HIGHSULF(TM) is easily applied to any units of the SCOT type for aftertreatment of tail gases. in refineries and petrochemical complexes. The advantage is the use of an inexpensive and widely available selective solvent -methyldiethanolamine (MDEA) and plant equipment. HIGHSULF(TM) processes are protected by US and Canadian patents and are being patented in other countries by TKK Company.